This invention relates to a novel polyimide which is high-temperature resistant and capable of being molded in a fused state, and also relates to a high-temperature resistant adhesive using the polyimide.
Polyimides obtained by the reaction of tetracarboxylic dianhydrides with diamines have so far been excellent in various properties and outstanding in high-temperature resistance. Therefore, the polyimides are expected to be widely used in the future for various fields where high-temperature resistance is required.
Many polyimides which have been developed to date exhibit excellent properties. Various polyimides, however, have an disadvantage in processing ability in that the polyimides have no glass transition temperature, even though they are excellent in high-temperature resistance, and must be processed by such methods as sinter molding when they are used as molding materials.
Various polyimides have a drawback of high water absorption which gives adverse effects on dimensional stability, insulative properties and solder heat resistance of molded products when they are used as materials for electric and electronic parts.
On the other hand, polyimide resins having excellent processing ability have also been developed. These resins, however, have low glass transition temperatures and are also soluble in halogenated hydrocarbons such as methylene chloride, and are thereby unsatisfactory in many cases from a high-temperature resistance and solvent resistance point of view.